Not just to keep them clean, but to always check and make sure there is no obvious damage anywhere. Take care of your guns and they will take care of you.
I take excellent care of my guns. I have guns with thousands of rounds through them that could practically pass for new. I just don't clean them after every time I shoot them.
Here's a thought experiment.
Person A goes to the range only once a year. Each year he makes his annual range trip, shoots 1000 rounds through his pistol, takes it home and cleans it immediately. He checks it over carefully during the cleaning process to insure that there is no damage, (obvious or otherwise), lubricates it properly and puts it back in the safe for a year.
Person B goes to the range, shoots 50 rounds through his pistol, takes it home wipes it down and puts it back in the safe. He repeats this process weekly until the round count reaches 500 rounds. At that point he cleans it, checking it over carefully to insure that there is no damage, lubricates it properly and puts it back in the safe until his next range trip in a week.
So who is taking better care of his gun? The guy who cleans only once a year, every 1000 rounds--
but after every range trip? Or is it the guy who cleans his gun 5 times a year, every 500 rounds, but only every 10 range trips?
The answer is that they are both taking good care of their guns but just taking different approaches. People too often assume that there's only one right way to do something and then make the jump to assuming that since their way works, it must be the only right way.
After a few trips to the range where I burned 1000 rounds in a day, I realized that it didn't hurt the gun to shoot it a lot between cleanings. I even did close up before and after pictures the first time I tried the experiment to see if I could detect any unusual wear as a result of firing that many rounds between cleanings and there was none--only the typical wear that 1000 rounds would normally generate.